n December 26th, 2004, the deadliest tsunami on record hit the South East Coast of Asia. “The Impossible” is based on the true story of one of the surviving families, and therefore embellished with soppy melodrama and a heightened sense of heroism and chaos (at one point the mother and son strain their outstretched arms to graze fingertips before being separated by gushing water), particularly when it comes to frenzied family interactions involving strength of spirit, morals, the contrived, disorganized switching of medical charts, and the bloodily physical destruction of flesh (thanks to the horror movie direction by J.A. Bayona, who previously helmed “The Orphanage”). Much of it is still effective, but the flow of the story occasionally breaks out of naturalness to overreach into fatigued amplification.

A generically annoying trio of children (Simon, Thomas and Lucas) accompanies Maria (Naomi Watts), a currently practice-less doctor, and Henry (Ewan McGregor), working in Japan, to the paradisiacal Thailand Orchid Beach resort for a Christmas vacation. A couple days in, without warning, massive waves of water crash onto the hotel and poolside decking where the boys are playing, submerging everything in aqueous pandemonium. All of the visitors are swept away (to the point where few other bodies are even seen in the vicinity) save for Maria and Lucas (Tom Holland), who struggle desperately to climb a tree for temporary safety – Maria has suffered severe wounds, including puncturing her abdomen and tearing loose a sizeable chunk of flesh from her right leg.

An eternity later, they are rescued by probing locals who drag the two bloodied survivors to a nearby village. From there, Maria is driven to a hospital where she receives brief medical attention before being prepped for surgery. She convinces Lucas to occupy himself with trying to help others; he has moderate success reconnecting separated families before he returns to his mother’s bedside, only to find that she’s been moved. Meanwhile, Henry miraculously resurfaces to begin the impossible search for his wife.

Language barriers, lack of resources, the heartbreaking refusal of a stranger to allow a cell phone call (and the equally affecting offer of a phone from a man saving batteries in the hope of hearing from his own family), all work to create a draining tale of Mother Nature doing her best to test a family’s endurance. The scenes of calamity are astounding, recreating large-scale wreckage and flooding to boost “The Impossible” into the realm of one of the great disaster movies. But the overdramatic aftermath is much more theatrically ruinous than the original tsunami, focusing greatly on earth-shattering coincidences: the father passing a few feet in front of the mother without seeing her, then the son spying the father from afar only to lose him in a crowd, and finally the children facing away from one another as they’re corralled into separate transports. The odds are presented so unbelievably that they detract from the sadness and immediacy of the group’s plight. What could have been a testament to familial bonds and a refusal to concede in the face of overwhelming detriment is instead a conspicuous endeavor to snag a few tears from viewers.

There’s a constant sense of foreboding (notably from the score), even during the calmer moments before the storm; the film never attempts to mask the terrifying nature of the tragedy at the heart of the story. It starts not with clever attempts at drawing emotions from the audience, but rather with blunt, staggering visuals to demand pity and sympathy. Roads littered with bodies, crying and screaming people wandering around in search of loved ones, the crowded hospital full of scattered injured, and the filth of bugs scurrying and fluids splattered about the building – the imagery certainly isn’t gentle (one of the climactic moments seems culled from the dreamlike imagery at the end of “Deliverance”). The perseverance, determination, and persistence are admirable (along with the first-rate production design and attention to detail), even if the end result is formulaic instead of unforgettable.